Thank you, I read about this story years ago, but this is a fuller telling of the story.
So much promise but I had not heard of any updates on progress on either Parkinson’s detection, or the identification of the metabolites that make the smell.
This in turn raises another question about the acute sense of smell, is this like the people who have four cones in the eye and so can see a whole set of colours?
I think this genetic mutation only occurs in women, I guess the genetics of olfaction are a lot more complicated.
Should photos be taken to accommodate for these four sets of cone colours, adding a new level for RGB? Very few people can see it, but there’s surely a demand.
My understanding of tetrachromacy is that it's duplicates the red cones, and shifts their sensitivity a very tiny amount - the suspicion is that it doesn't meaningfully change subjective color perception at all, and at best makes tetrachromats very slightly better at distinguishing shades of red that would appear identical to us regular trichromats.
It would be very exciting if some humans had a mutation that let them be sensitive to something further than our standard three!
(There was a footnote in Seeing like a State about some doctor with an apprentice approaching a house and saying "smell this, this is the smell of [some infectious disease]")
